Song HS  Kwon SJ  Epling WS  Croiset E  Nam SC  Yi KB

Methane partial oxidation CO2 reforming Oxidative reforming Hydrotalcite

Partial oxidation, CO2 reforming and the oxidative CO2 reforming of CH4 to produce synthesis gas over supported Ni hydrotalcite-type (Ni0.5Mg2.5Al catalyst) catalysts were carried out and the effects of metal supports (i.e.; Mg and Ca) on the formation of a stable double-layer structure on the catalysts were evaluated. The CH4 reforming stability was determined to be affected by the differences in the interaction strength between the active Ni ions and support metal ions. Only a Ni-Mg-Al composition produced a highly stable hydrotalcite-type double-layered structure; while the Ni-Ca-Al-type composition did not. Such structure provides excellent stability for the catalyst (-80% efficiency) as confirmed by the long-term CO2 reforming test(-100 h), while the Ni-Ca-Al catalyst exhibited deactivation phases starting at the beginning of the reaction. The interaction strength between the active metal (Ni) and the supporting components (Mg and Al) was determined by temperature-programed reduction (TPR) analyses. The affinity was also confirmed by the TPR temperature because the Ni-Mg-Al catalyst required a higher temperature to reduce the Ni relative to the Ni-Ca-Al catalyst. The highest initial activity for synthesis gas production was observed for the Ni0.5Ca2.5Al catalyst; however, this activity decreased quickly due to coke formation. The Ni0.5Mg2.5Al catalyst exhibited a high reactivity and was more stable than the other catalysts because it had a higher resistance to coke formation.